Problem: What is the least common multiple of 40 and 30? Another way to say this is: $\lcm(40, 30) = {?}$
Solution: The least common multiple is the smallest number that is a multiple of 40 and 30. We know that 40 x 30 (or 1200) is a common multiple, but is it the least common multiple? Write out the multiples of 40 until we find a number divisible by 30. 40, 80, 120, So, 120 is the least common multiple of 40 and 30.